keeping url parameters during pagination - php

Question

Is there any way to keep my GET parameters when paginating.
My problem is that I have a few different urls i.e
questions.php?sort=votes&author_id=1&page=3
index.php?sort=answers&style=question&page=4
How in my pagination class am I supposed to create a link to the page with a different page number on it but yet still keep the other parts of the url?

Answer 1

If you wanted to write your own function that did something like http_build_query, or if you needed to customize it's operations for some reason or another:
<?php
function add_edit_gets($parameter, $value) {
$params = array();
$output = "?";
$firstRun = true;
foreach($_GET as $key=>$val) {
if($key != $parameter) {
if(!$firstRun) {
$output .= "&";
} else {
$firstRun = false;
}
$output .= $key."=".urlencode($val);
}
}
if(!$firstRun)
$output .= "&";
$output .= $parameter."=".urlencode($value);
return htmlentities($output);
}
?>
Then you could just write out your links like:
Click to go to page 2

Answer 2

You could use http_build_query() for this. It's much cleaner than deleting the old parameter by hand.
It should be possible to pass a merged array consisting of $_GET and your new values, and get a clean URL.
$new_data = array("currentpage" => "mypage.html");
$full_data = array_merge($_GET, $new_data); // New data will overwrite old entry
$url = http_build_query($full_data);

Answer 3

In short, you just parse the URL and then you add the parameter at the end or replace it if it already exists.
$parts = parse_url($url) + array('query' => array());
parse_str($parts['query'], $query);
$query['page'] = $page;
$parts['query'] = http_build_str($query);
$newUrl = http_build_url($parts);
This example code requires the PHP HTTP module for http_build_url and http_build_str. The later can be replaced with http_build_query and for the first one a PHP userspace implementation exists in case you don't have the module installed.
Another alternative is to use the Net_URL2 package which offers an interface to diverse URL operations:
$op = new Net_URL2($url);
$op->setQueryVariable('page', $page);
$newUrl = (string) $op;
It's more flexible and expressive.

Answer 4

How about storing your page parameter in a session, so you don't have to modify every single page url?